If you're interested in testing/comparing two batteries to each other, you'll have to go about it in a different way. I think what these people are trying to get across to you, oleg, is standby/idle time is inaccurate. Although they didn't go about it in a very nice way and your observations are totally accurate about the usage, they're still correct. Let me try to explain it to you so we can all be on the same page.
I have two batteries - the stock one and one I bought as a backup to the stock one - which drain differently, but overall have the same usage. The stock drains at about 2-3% on idle, while the backup drains 1% every hour or so, so it seems like the replacement is better. However, after testing both of them, I've realized they are almost the exact same. Although you might notice a slower decline in usage in idle time, you might notice an incline in usage during those times when you're really using your phone; this was the case with my backup.
Pretty much if you want an accurate test, you're going to have to replicate a situation where you battery drains constantly and at a pretty decent rate. My method was:
Setup: Increase brightness to 100%, find a widget that disables screen timeout (I use "Screen Timeout Toggle"), put that widget on your home screen, find a CPU controlling application like SetCPU, and create a profile which makes the CPU run at the highest frequency for both Min and Max.
1. Completely discharge battery until phone turns off
2. Plug phone into outlet and turn it on (if it doesn't so on its own)
3. Wait until it reaches 100% and then wait another 20 minutes
4. Unplug phone and record the time
5. Quickly, toggle the widget to make your screen always on, enable that CPU profile which I mentioned in the Setup, and leave your phone on somewhere you can monitor it.
6. Once it reaches something below 5%, keep a closer eye on it
7. Once it reaches 1%, go to your battery graph and take a screenshot of both the battery usage distribution section, and the main graph that shows when your screen was on, etc.
8. Once your phone turns off completely, record that time.
9. Repeat for second battery
Unfortunately this method will eat up an entire day, and if you're someone who constantly gets messages/texts, you'll have to use airplane mode or something to keep external, uncontrollable factors from using up your battery.
Finally, when you review this, post your kernel/ROM/settings which you tested with, along with the screenshots for comparison, while also explaining everything.